1. Field of the Invention
The present invention relates to a fan frame structure, and more particularly to a fan frame having a plurality of grooves for providing extra air entrances to increase the amount of air sucked into and through a fan unit thereof.
2. Description of Prior Art
Basically, a fan unit is utilized to promote air circulation for heat dissipation. The better the air circulation is, the more effective the heat dissipation is. FIG. 3 and FIG. 4 show a conventional axial-flow fan 100 for heat dissipation. The fan 100 includes a fan frame 101 and an impeller 102 encircled by the fan frame 101. An air passage 103 is formed between the impeller 102 and an inner periphery of the fan frame 101. The passage 103 defines an air inlet 104 and an opposite air outlet 105. The impeller 102 of the fan 100 is further connected with a motor 106 for providing forced airflow during operation.
The arrows shown in FIG. 2 represent the airflow passage produced by the fan 100. However, it is noticed that the disadvantage of this prior art fan 100 resides in that the source of air sucked into and through the fan 100 is restricted to only the axial airflow flowing from the top to the bottom through the air passage 103 and the amount of air through the fan 100 is limited subject to the narrowed air inlet 104. Thus the heat dissipation effect of the fan 100 is not satisfactory.
In order to increase the amount of air through a fan unit, measures such as increasing the rotation speed of the motor or enlarging the size of the air inlet are under consideration. But unfortunately, high rotation speed of the motor will inevitably result in an unpleasant noise. Moreover, larger the air inlet is, more spaces the fan unit will occupy, which conflicts with the tendency of miniaturization of a system casing in which the fan unit is received.
Therefore, it is desired to design a novel fan frame structure to overcome the aforementioned problems and increase the amount of air through the fan unit for promoting the heat dissipation thereof.